[RDF] Re: RDF::Service vs. RDF API

[Jonas Liljegren]

Alberto Reggiori <alberto.reggiori@jrc.it> writes:

> I saw your announcement about RDF::Service and I found it very
> interesting because I am trying to build something similar using Perl TIE
> interface over a Berkeley DB TCP/IP based DBMS we built.

Maby you would like to join the project? :)


> I am just wondering now how all this WRAF work [1]
> relate to the proposed API draft of Sergey Melnik [2]

I have followed and participated in the API discussion from the first
RADIX proposal.  The API is influenced by this discussion.

The API structure will be compatible. We will use moels and virtual
models as the base for operations.  We will have equivalent methods
with the same name, like add(), contains(), create(), elements(),
find(), etc.

But the implementation will be done the Perl way.  The basic operations
uses the subject resource.  In principal, we are trying to achive
this:

$person_email = $model->get($person_uri)->home->online->email->value;

A property is a method is a property.  Filters/specifiers/queries can
be supplied along the call path:

$person_name = $person->first_name(according_to=>$this_person)->value;


> and if there is a Perl implementation of it (a part pro-solutions one)

RDF::Service is a alpha release of the Wraf core module.  It *is*
working code.  A sample CGI program is included.  It uses the included
RDF::Service::Interface::DBI::V01 to implement a simple person
database.  You can list, view, create, adit and delete person records.


> I understand that the RDF::Service approach is a bit wider in scope (caching, CORBA
> DII like interface) but it seems to me that the main difference is
> about how you access/query the underling model. 

The implementation work is focused on the practical neads and goals of
what we want to do.  All the functionality will be implemented as
needed.  We will start with limited implementations and expand each
aspect then this is required.  The functions implemented are a direct
result of what the example applications require.

I just create the interface that I would like to use myself.  And Perl
lets me do just that. :-)

> Any pointer to a discussion about it?

Join the Wraf mailing list:

        http://www.uxn.nu/cgi-bin/mailman/listinfo/rdf

The archive can be find here:

        http://www.uxn.nu/pipermail/rdf/2000/thread.html



> What is good or bad of the two different views?

I think that the biggest diffrence between Wraf and other RDF
implementations is the interface system that lets you combine many
data sources.  You can create interfaces to existing systems and
authorized additions in the RDF::Service will directly update the
backend system.


> [1] http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/~checkout~/RDF-Service/doc/api.html?rev=1.3&content-type=text/html&cvsroot=wraf
> [2] http://www-db.stanford.edu/~melnik/rdf/api.html


-- 
/ Jonas  -  http://jonas.liljegren.org/myself/en/index.html